• 当前 Bug 的表现（可附上截图）

font-weight:500;letter-spacing:4rpx

获取焦点后字重和字距失效， 失去焦点后恢复正常

• 预期表现

正常情况下字重不会改变

• 复现路径

开发者工具显示正常

在iphone8 小米6等真机上复现

• 提供一个最简复现 Demo

<input class="editText {{phoneFocus?'borderRed':''}}"
       placeholder-class="editText-placeholder" bindinput="phone" maxlength="11"
       name='phone'
       data-value='phone' bindblur='inputBlur'
       bindfocus='inputFocus' type='number' placeholder='请输入手机号'/>

<input class="editText {{passwordFocus?'borderRed':''}}" placeholder-class="editText-placeholder"
       bindinput='password' type='password' bindfocus='inputFocus'
       bindblur='inputBlur' data-value='password'
       placeholder='请输入登录密码'/>

input{height:108rpx;caret-color:#fc5a44;font-size:35rpx;font-weight:500;letter-spacing:4rpx;line-height:69rpx;}

.borderRed{border-bottom: 1px solid #fc5a44!important;}
.editText{color:rgba(36,39,46,1);border-bottom: 1px solid rgba(238,237,243,1);}
.editText-placeholder{color:rgba(200,201,204,1);}